The aim of this article is to examine the addressing models and investigate cross-layer interactions of different mobility protocols. One of the interesting questions is how mobility should be handled and coordinated when there are multiple layers offering support for mobility. We also consider the case of the hop-by-hop routed layer-7 environment, implemented typically using SOAP (W3C, 2003), CORBA, or SIP in the telecommunications sector. These three technologies are the most frequently used, have differing characteristics and product bases, and contain the essence of middleware/application layer communication. SOAP is an abstract and generic messaging framework with extendable header system, allowing rich facilities for hop-by-hop propagation of messages.